Signs of jaundice spreading from the head downwards with increasing severity (cephalocaudal progression) can be observed, but visual assessment alone is not reliable for severity assessment NICE CKS.
Examine the sclerae and gums, and press lightly on the skin to check for signs of jaundice in 'blanched' skin, especially in the first 72 hours NICE CG98.
Signs of illness such as lethargy, poor feeding, irritability, vomiting, or hypotonia followed by hypertonia suggest more severe hyperbilirubinaemia or bilirubin encephalopathy NICE CKS.
Dark urine and pale stools can indicate underlying liver issues and are signs to consider in severity assessment NICE CKS.
Features like a rapidly rising bilirubin level (>8.5 μmol/litre per hour) and clinical signs of acute bilirubin encephalopathy are critical indicators of severity NICE CKS.